# Thread: The Relativity of Simultaneity

1. Originally Posted by quantum_wave
Very interesting. What is the SR explanation for this outcome?

I win Enmos.
SR has no explanation, because:

1. SR assumes the speed of light is always measured to be c in all frames (which it is clearly NOT in this correct example)

2. SR assumes length contraction, which will prove to be incorrect in this example.

3. SR assumes the box is at rest, and that the box doesn't have a velocity, because Einstein doesn't acknowledge that the box could have an absolute velocity.

2. Originally Posted by Motor Daddy
Ok, You want the simple answer? The simple answer is, I know what the speed of light is because the unit of measure of distance is defined by the time of light travel in vacuum.
Super. Just so there is no confusion. The speed of light was measure to a high degree of accuracy and the speed was found to be 299 792 458 m/s. The meter was then defined as distance light travels in 1/299,792,458 of a second or of course 1 meter.

3. Originally Posted by origin
Super. Just so there is no confusion. The speed of light was measure to a high degree of accuracy and the speed was found to be 299 792 458 m/s. The meter was then defined as distance light travels in 1/299,792,458 of a second or of course 1 meter.
Who cares??? I just defined a new standard unit of measure, and without measuring it, I know the speed of light is EXACTLY 2 htdltios/second.

I don't need to measure it, it is defined!

4. Originally Posted by Motor Daddy
SR has no explanation, because:

1. SR assumes the speed of light is always measured to be c in all frames (which it is clearly NOT in this correct example)

2. SR assumes length contraction, which will prove to be incorrect in this example.

3. SR assumes the box is at rest, and that the box doesn't have a velocity, because Einstein doesn't acknowledge that the box could have an absolute velocity.
I would like to hear what James R and Ned have to say at this point, i.e. do they confirm your scenario and what are the objections.

5. Originally Posted by quantum_wave
Very interesting. What is the SR explanation for this outcome?

I win Enmos.
The problem with MD problem is very basic. He assumes that the speed of light varies with the speed of the observer or source.

SR does NOT assume the speed of light is always measured as c. It would be stupid to assume things not in evidence and then to construct a theory based on those assumptions.

SR simple uses the facts in evidence - namely that the speed of light is always measured as c regardless of the velocity of the source or the observer. The speed of light for all light measurements are the same. Light has been measiured millions of times over the past 100 years - it doesn't vary it is unaffected by the reference frame.

I am sorry that you don't like that is true. I don't really have any sort of idea how to help you throught this. The measurements are there. You can choose to ignore the measurements and instead make up a scenario that ignores the real numbers, but I cannot figure out why you would do that.

6. Originally Posted by quantum_wave
I would like to hear what James R and Ned have to say at this point, i.e. do they confirm your scenario and what are the objections.
James R has already tried and failed to give the correct times and locations.

Neddy Bate is the one that taught me how to use the 3D coordinates, and how to check if they are correct.

Neddy bate has previously told me these numbers are correct. I can get the quote if he has forgotten, which I'm sure he hasn't.

7. Originally Posted by origin
The problem with MD problem is very basic. He assumes that the speed of light varies with the speed of the observer or source.

SR does NOT assume the speed of light is always measured as c. It would be stupid to assume things not in evidence and then to construct a theory based on those assumptions.

SR simple uses the facts in evidence - namely that the speed of light is always measured as c regardless of the velocity of the source or the observer. The speed of light for all light measurements are the same. Light has been measiured millions of times over the past 100 years - it doesn't vary it is unaffected by the reference frame.

I am sorry that you don't like that is true. I don't really have any sort of idea how to help you throught this. The measurements are there. You can choose to ignore the measurements and instead make up a scenario that ignores the real numbers, but I cannot figure out why you would do that.
Then you will show me how my times, distance, velocities, and coordinate locations are incorrect in the 3D example? Will you also tell me in which direction you measure the speed of light to be c in the cube?

Certainly you can back up your assertions. I've already told you my answers, I'll await yours. You do know the coordinates, don't you? Please don't tell me you live in a illusion, and that your numbers don't correspond to reality. I want the coordinates, times, and velocities in the example, please.

8. Originally Posted by Motor Daddy
Who cares??? I just defined a new standard unit of measure, and without measuring it, I know the speed of light is EXACTLY 2 htdltios/second.[\QUOTE]
Yes and your definition is 100% based on the speed of light measured on earth. The light speed has been shown time and time again to be completely indedendent of the motion of the measuring device.

I don't need to measure it, it is defined!
Course you don't need to measure it because it will not change. It is always measured at the same speed whether the source or the observer is in motion.

9. Originally Posted by origin
SR does NOT assume the speed of light is always measured as c. It would be stupid to assume things not in evidence and then to construct a theory based on those assumptions.
I agree, it would be stupid. Do you happen to know Einstein's second postulate? You know, the basic assumption he bases his theory on.

10. sorry got to earn some money. maybe if I feel like banging my head against the wall and talking to a rock I will check back later.

11. Originally Posted by origin
The problem with MD problem is very basic. He assumes that the speed of light varies with the speed of the observer or source.

SR does NOT assume the speed of light is always measured as c. It would be stupid to assume things not in evidence and then to construct a theory based on those assumptions.

SR simple uses the facts in evidence - namely that the speed of light is always measured as c regardless of the velocity of the source or the observer. The speed of light for all light measurements are the same. Light has been measiured millions of times over the past 100 years - it doesn't vary it is unaffected by the reference frame.

I am sorry that you don't like that is true. I don't really have any sort of idea how to help you throught this. The measurements are there. You can choose to ignore the measurements and instead make up a scenario that ignores the real numbers, but I cannot figure out why you would do that.
You don't have to be sorry because what I like and don't like doesn't change anything. You do realize that the measurements work in SR because the coordinate system is designed to make sure the math works, right? Einstein reconciled the invariant speed of light in all frames with the principle of relativity as I understand the process by employing Lorentz transformations. But I'm a layman so you can expect I don't have the rigor behind my understanding.

12. Originally Posted by origin
sorry got to earn some money. maybe if I feel like banging my head against the wall and talking to a rock I will check back later.
Are you sure you can do those two things at the same time?

Have you been banging your head on the wall while you talk to a rock for quite some time now?

If I were you, I would seek professional help immediately!!!

13. Originally Posted by quantum_wave
You do realize that the measurements work in SR because the coordinate system is designed to make sure the math works, right?
That makes no sense. You can walk outside tonight and shoot a laser at the moon and have a detector to measure the time it takes for the entire round trip and calculate the speed of the light. It has nothing to do with cooridinate system.

Better yet measure the time it takes for the the round trip when the moon is in front of the direction of the earths orbit around the sun and then do it when the moon is behind the direction of the earths orbit around the sun.

MD says the time will be different because the relative speed of light will be different due to the motion of the earth.

Wait!! You better not measure it because that will show that speed of light is the same in both cases which would mean MD is wrong. Yikes! Best just to live in blissful ignorance.....

14. Originally Posted by origin
That makes no sense. You can walk outside tonight and shoot a laser at the moon and have a detector to measure the time it takes for the entire round trip and calculate the speed of the light. It has nothing to do with cooridinate system.

Better yet measure the time it takes for the the round trip when the moon is in front of the direction of the earths orbit around the sun and then do it when the moon is behind the direction of the earths orbit around the sun.

MD says the time will be different because the relative speed of light will be different due to the motion of the earth.

Wait!! You better not measure it because that will show that speed of light is the same in both cases which would mean MD is wrong. Yikes! Best just to live in blissful ignorance.....
If by "round trip" you mean the light traveling from earth to the moon and back again, your experiment doesn't work. It is not able to differentiate between an absolute reference frame and relativity. In relativity, the light beam will simply take the same amount of time back and forth, but in an absolute frame the first part of the trip will be longer and the second will be shorter. The total round trip time will be the same.

That's my understanding anywho.

15. Originally Posted by origin
That makes no sense. You can walk outside tonight and shoot a laser at the moon and have a detector to measure the time it takes for the entire round trip and calculate the speed of the light. It has nothing to do with cooridinate system.

Better yet measure the time it takes for the the round trip when the moon is in front of the direction of the earths orbit around the sun and then do it when the moon is behind the direction of the earths orbit around the sun.

MD says the time will be different because the relative speed of light will be different due to the motion of the earth.

Wait!! You better not measure it because that will show that speed of light is the same in both cases which would mean MD is wrong. Yikes! Best just to live in blissful ignorance.....
Perhaps I just don't understand Chapter 11: http://www.marxists.org/reference/ar...ative/ch11.htm

16. Originally Posted by quantum_wave
I would like to hear what James R and Ned have to say at this point, i.e. do they confirm your scenario and what are the objections.

I shall try to summarize everything for you. MD says that the speed of light in vaccuo measures exactly c=299792458m/s in only one frame of reference. I call that frame of reference his "absolute rest frame". MD says that any frame which has "absolute motion" cannot possibly measure the speed of light in vaccuo to be c=299792458m/s.

All of the experimental evidence we have says that MD is wrong. For example, GPS provides experimental proof that the speed of light cannot vary as much as MD say it does. In order for GPS to be accurate, the travel times of the signals from satellite directly to the surface of the earth should not vary by more than 0.00000001 second over one full orbit of the satellite. Yet GPS does work, so we know the travel times are not varying by much at all, and that supports the idea that the speed of light is constant relative to earth. If MD's theory were correct, that would mean the earth must not be moving faster than 0.003km/s. Yet we know this cannot be possible, because the speed of the earth relative to the sun is about 29km/s. That is why the physics community embraces the theory of Relativity, rather than the theory of Motor-Daddity.

However, there was a time when I helped MD make some equations to go with his theory. He tended to make examples where the moving frame only moved in one dimension, like this:

Originally Posted by Neddy Bate
OK so you have given me these times:
$t_x = 1.38493$
$t_y = 0.65000$
$t_z = 0.65000$

By my calculations, the velocity components look like this:
$v_x = 0.63897c$
$v_y = 0.00000c$
$v_z = 0.00000c$

At time 1.38493, the center of the "x-face" is located at point (1.38493, 0.000, 0.000) and the distance from that point to the origin is:
$d = sqrt(1.38493^2 + 0.00000^2 + 0.00000^2)$
$d = 1.38493$

At time 0.65000, the center of the "y-face" is located at point (0.41533, 0.50000, 0.00000) and the distance from that point to the origin is:
$d = sqrt(0.41533^2 + 0.50000^2 + 0.00000^2)$
$d = 0.65000$

Yes, everything matches your calculations. Good job!

But the equations he likes to use only work in one-dimensional cases. If you want it to work in 3-dimensional cases, you need the more complicated equations that I helped him with. But if experimental evidence does not support the theory of Motor-Daddity, then all the equations in the world won't make it correct.

17. Originally Posted by Neddy Bate
I shall try to summarize everything for you. MD says that the speed of light in vaccuo measures exactly c=299792458m/s in only one frame of reference. I call that frame of reference his "absolute rest frame". MD says that any frame which has "absolute motion" cannot possibly measure the speed of light in vaccuo to be c=299792458m/s.

All of the experimental evidence we have says that MD is wrong. For example, GPS provides experimental proof that the speed of light cannot vary as much as MD say it does. In order for GPS to be accurate, the travel times of the signals from satellite directly to the surface of the earth should not vary by more than 0.00000001 second over one full orbit of the satellite. Yet GPS does work, so we know the travel times are not varying by much at all, and that supports the idea that the speed of light is constant relative to earth. If MD's theory were correct, that would mean the earth must not be moving faster than 0.003km/s. Yet we know this cannot be possible, because the speed of the earth relative to the sun is about 29km/s. That is why the physics community embraces the theory of Relativity, rather than the theory of Motor-Daddity.

However, there was a time when I helped MD make some equations to go with his theory. He tended to make examples where the moving frame only moved in one dimension, like this:

But the equations he likes to use only work in one-dimensional cases. If you want it to work in 3-dimensional cases, you need the more complicated equations that I helped him with. But if experimental evidence does not support the theory of Motor-Daddity, then all the equations in the world won't make it correct.
Thank you Ned, you're a gentleman.

18. Originally Posted by Neddy Bate
I shall try to summarize everything for you. MD says that the speed of light in vaccuo measures exactly c=299792458m/s in only one frame of reference. I call that frame of reference his "absolute rest frame". MD says that any frame which has "absolute motion" cannot possibly measure the speed of light in vaccuo to be c=299792458m/s.

All of the experimental evidence we have says that MD is wrong. For example, GPS provides experimental proof that the speed of light cannot vary as much as MD say it does. In order for GPS to be accurate, the travel times of the signals from satellite directly to the surface of the earth should not vary by more than 0.00000001 second over one full orbit of the satellite. Yet GPS does work, so we know the travel times are not varying by much at all, and that supports the idea that the speed of light is constant relative to earth. If MD's theory were correct, that would mean the earth must not be moving faster than 0.003km/s. Yet we know this cannot be possible, because the speed of the earth relative to the sun is about 29km/s. That is why the physics community embraces the theory of Relativity, rather than the theory of Motor-Daddity.

However, there was a time when I helped MD make some equations to go with his theory. He tended to make examples where the moving frame only moved in one dimension, like this:

But the equations he likes to use only work in one-dimensional cases. If you want it to work in 3-dimensional cases, you need the more complicated equations that I helped him with. But if experimental evidence does not support the theory of Motor-Daddity, then all the equations in the world won't make it correct.
You've not proven anything about GPS because it has so many variables, and it is constantly updated. I don't know enough about GPS to tell you where you go wrong, and you are no GPS expert either.

I asked you to tell me how far away from the surface of the earth a GPS satellite is. You never responded. If you think I'm just going to throw my hands up in the air because you said GPS says the earth has an absolute zero velocity you are mistaking. Do you actually believe the Earth has an absolute zero velocity???No, you don't, so you've proven yourself wrong by saying GPS wouldn't work if the earth had an absolute velocity greater than zero.

Now onto more important matters. What direction in the cube can you measure the speed of light to be c??

19. Originally Posted by quantum_wave
Thank you Ned, you're a gentleman.

Your welcome, and likewise. By the way, I completely understand your curiosity over how nature manages to make the speed of light the same in all reference frames. It took me a long time to figure out how special relativity works, and that was with the help of some really smart people on this forum. If you have any questions, I'd be happy to help. But don't be surprised if it takes awhile before all of the pieces of the puzzle finally start to fit together.

20. Originally Posted by Neddy Bate
Your welcome, and likewise. By the way, I completely understand your curiosity over how nature manages to make the speed of light the same in all reference frames. It took me a long time to figure out how special relativity works, and that was with the help of some really smart people on this forum. If you have any questions, I'd be happy to help. But don't be surprised if it takes awhile before all of the pieces of the puzzle finally start to fit together.
I do have a question. In the link I just gave Origin, to chapter 11, the equations use the square root of I minus v^2/c^2. I am assuming that I is 1. Is that right?

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